PROJECT SUMMARY/ABSTRACT Patterns of tobacco use may change dramatically as a result of the new vaporized nicotine products (VNPs), such as e-cigarettes. The use of VNPs has surged, which is likely driven by the perception that they are less harmful than regular cigarettes and are useful smoking cessation aids. At the population level, however, their use may delay cessation of cigarettes by employing VNPs as ?bridge? products to avoid smoking restrictions, and may attract never smokers that may later become smokers. The uptake and use of these products will be influenced by the regulatory context in which they are brought to market. In dynamic situations such as these, modeling provides a ?virtual laboratory? to synthesize existing evidence and compare the impact of multiple policies and regulations on health outcomes. The specific aims of the proposed project are: Aim 1, Develop a conceptual framework for predicting the impact that tobacco control policies have on VNP and smoked tobacco use rates. Inputs and parameters will be developed in conjunction with the Project Leaders in this Program Project, and based on the relevant literature and the advice of outside expert panels. Aim 2: Develop an economic model of tobacco industry behavior and product regulation. Product use will depend on appeal, addiction, and acute toxicity, as determined by industry pricing, product content, and marketing. The model will distinguish the role of traditional cigarette and specialized VNP firms in the evolution of the VNP market and consider how cigarette and VNP industry dynamics are influenced by various regulatory options. Aim 3: Develop models that would examine trends in VNP and cigarette use, the effects of policies on use, and health consequences. Models of cigarette and VNP use will be developed for the Canada, England, and the US that will be used to examine the potential role of policies aimed at cigarettes and VNP use in each nation and compared to the other nations. Results will be disseminated to inform the FDA and other regulatory agencies and provide documentation and results in user friendly formats. Aim 4: Build comparable models for middle and low income countries, with adequate local data. We will compare the role of supply vs demand-reducing policies affecting the VNP and cigarette use and associate health effects.